The present invention relates to a shifting mechanism.
Modern automatic passenger car transmissions and so-called “automated manual transmissions” frequently have a so-called “two-channel shifting mechanism,” that is, they can optionally be operated in an automatic mode or can be manually shifted by way of a so-called touch shifting mechanism.
DE 199 38 528 A1 disclosed an automatic transmission with a two-channel shifting mechanism. By way of a linkage or a Bowden cable, the gear shift lever is mechanically connected with the transmission and can optionally be moved in a left or in a right shifting channel. By way of the left shifting channel, the individual operating conditions of a conventional transmission can be selected, specifically, the parking condition, the reversing condition, the neutral condition and the drive condition, in which individual forward gears are automatically shifted by a transmission control. From the drive condition, the gear shift lever can automatically be moved into the “right shifting channel,” in which manual shifting is possible which is hereinafter called a “step-by-step shifting condition.” In the right shifting channel, the shifting lever has a stable center position and can optionally be pressed toward the front or “touched” toward the rear, which permits a manual upshifting or downshifting.
An object of the invention is to provide a shifting mechanism for an automatic transmission which is improved with respect to its shifting ergonomy and which, in particular, better meets the demands of sporty vehicles, for example, to prevent faulty operation.
One aspect of the invention concerns “monostable shifting,” where two shifting channels are provided. “Monostable” means that the shifting element or the shift lever has only a single stable position. As a function of the actual “operating condition” of the shifting mechanism, certain other operating conditions can be selected by deflecting the shift lever. For this purpose, the shift lever is manually deflected either in one or the other shifting channel and, after being released, automatically returns from any possible deflected position to the stable starting position.
Preferably, two parallel shifting channels are provided which are arranged side-by-side. In its stable position, the shifting element or the shift lever is situated in one of the two shifting channels which, for the purpose of differentiation, is called a “first shifting channel.” The shift lever can be touched in the first shifting channel, that is, it can be swivelled toward the front or the rear. The shift lever can also be moved from the stable position in a direction transverse to the shifting channels into a center position of the other shifting channel which is called a second shifting channel. From the center position in the second shifting channel, the shift lever can be moved either toward the front into a forward neutral position or still farther into a forward end position or toward the rear into a rearward neutral position or still farther into a rearward end position.
It is explicitly pointed out that the terms “forward” or “rearward” as well as “left” or “right” in the following description and in the claims are not understood to necessarily be spatial and are definitely not limiting. These terms are selected only for a clear differentiation of the individual positions.
As a function of the actual operating condition of the shifting mechanism, the reversing condition, the neutral condition or the drive condition can be selected by way of the shift lever in the second shifting channel. The first shifting channel is provided for the step-by-step shifting condition. The selection of individual driving operation conditions will be explained in detail in connection with the drawing.
According to a further development of the invention, the reversing condition is selected by a movement of the shift lever toward the “forward left,” as in the case of many conventional manual transmissions. This means that, for selecting the reversing condition, the shift lever is moved from the stable position toward the left into the second shifting channel and from there toward the front into its forward end position. Thus, a driver who is accustomed to a conventional manual transmission does not have to adapt himself for selecting the reversing condition.
For selecting the drive condition, that is, the “automatic mode,” in which the individual forward gears of the transmission are automatically shifted by a transmission control, the shift lever has to be moved toward the “rearward left.” This means that the shift lever has to be moved from its stable center position first transversely into the second shifting channel and then into its rearward end position.
To select the neutral condition as a function of the actual operating condition, the shift lever must be moved into the forward neutral position, which is situated between the center position and the forward end position in the second shifting channel, or into the rearward neutral position which is situated between the center position and the rearward end position in the second shifting channel. When the shifting mechanism is in the reversing condition, the shifting element has to be moved into the rearward neutral position for this purpose. If, in contrast, the shifting mechanism is in the drive condition, the shifting element has to be moved into the forward neutral position.
According to a further development of the invention, a shift into the neutral condition automatically takes place when the shifting mechanism is in the reversing condition and the shifting element is moved in the longitudinal direction of the first shifting channel.
According to a further development of the invention, the step-by-step shifting condition can be selected only when the shifting mechanism is in the drive condition. This means that, from the reversing condition or the neutral condition, a shift directly into the step-by-step shifting condition cannot be made for reasons of safety.
When the shifting mechanism is in the drive condition, a change into the step-by-step shifting condition can easily and comfortably take place. For this purpose, the shifting element or shift lever only needs to be deflected from its stable position in the longitudinal direction of the first shifting channel, that is, the shift lever only needs to be touched briefly.
When the shifting mechanism is in the drive condition and if the shift lever is slightly touched in the first shifting channel, a shift into the step-by-step shifting condition takes place. The step-by-step shifting condition can also be called an “M Program” (Manual Shifting Program). During the first touch of the shifting element for a shift out of the drive condition, it may be provided that the momentary gear be held. When the shifting mechanism is in the step-by-step shifting condition and the shift lever is deflected from its stable position toward the front or rear, a “manual” upshift or downshift takes place, that is, a shift takes place only if the driver operates the shift lever in the first shifting channel.
Furthermore, a sports program (S Program) may be provided. From the drive condition, a shift into the S Program may take place, for example, by operating an “S/D key.” However, a shift from the drive condition into the S Program may also take place by a one-time touching of the shift lever in the first shifting channel. The S Program is a “second automatic mode” which differs from the automatic mode of the drive condition with respect to its shifting characteristics. It may, for example, be designed as a “Sports Program” in that the individual shifts take place at higher speeds. From the S Program, a manual upshifting or downshifting can take place by moving the shift lever in the first shifting channel.
It was mentioned above that, possibly for safety reasons, it may be provided that the step-by-step shifting condition or the S Program can be selected only when the shifting mechanism is actually in the drive condition. For this purpose, a “monitoring device” is provided. The monitoring device may be a “passive” electronic safety system which, during a longitudinal movement of the shifting element in the first shifting channel, permits a shift into the step-by-step shifting condition only when the shifting mechanism is in the drive condition. This means that, although the electronic monitoring system permits a movement of the shifting element in the first shifting channel in any operating condition, it allows a shift into the step-by-step shifting condition only when the shifting mechanism is in the drive condition.
As an alternative, a mechanical blocking device may be provided which permits a longitudinal movement of the shifting element or shift lever in the first shifting channel only when the shifting mechanism is in the drive condition or when the step-by-step shifting condition is already active and the driver wants to upshift or downshift manually.
According to a further development of the invention, the shifting mechanism can be shifted from the step-by-step shifting condition by way of two different deflection paths of the shifting element into the drive condition. As mentioned above, the drive condition can, on the one hand, be selected by moving the shift lever “to the rearward left,” that is, from the stable position into the second shifting channel and then into one of the two end positions. In addition, there is the possibility of selecting the drive condition by an “opposed” transverse movement. The drive condition can therefore also be selected by a transverse movement from the stable position into a position which is opposed to the second shifting channel. If, for example, the second shifting channel is situated on the left next to the stable position of the shift lever or on the left next to the first shifting channel, the drive condition can be selected by moving the shift lever toward the “rearward left” or by a transverse movement toward the right. This additional selection possibility for the drive condition considerably improves the shifting comfort because the driver only has to move the shift lever into a transverse direction toward the right.
It may preferably be provided that, as a result of the above-mentioned additional “degree of transverse freedom” of the shift lever, a shift can take place between the automatic mode of the drive condition, the step-by-step shifting condition (M Program) and the sports program (S Program).
In addition, an “operating element” is preferably provided for selecting a parking condition. The operating element may, for example, be an electric key which is integrated in the shifting element or the shift lever. Optionally, a second “operating element” may be provided for selecting the parking condition, which operating element may, for example, be coupled with a switching device for the “switching-on or switching-off” of a vehicle power supply. The second operating element can be formed, for example, by the ignition lock or an “off switch” so that, when the vehicle is parked, the shifting mechanism automatically shifts into the parking condition.
As a function of the actual operating condition, the shifting possibilities can be summarized as follows:
In the parking condition, the neutral condition can be selected by deflecting the shifting element from the stable position into the forward or rearward neutral position. The drive condition or the reversing condition can be selected by deflecting the shifting element into one of the two end positions of the second shifting channel. At least in the case of “true” automatic vehicles, the step-by-step shifting condition cannot be selected directly from the parking condition.
In the reversing condition, the neutral condition can be selected by deflecting the shifting element from the stable position into the rearward neutral position of the second shifting channel. The drive condition can be selected by deflecting the shifting element into the rearward end position. At least in the case of “true” automatic vehicles, the step-by-step shifting condition also can not be selected from the reversing condition.
In the neutral condition, the reversing condition can be selected by deflecting the shifting element from the stable position into the forward end position. The drive condition can be selected by deflecting the shifting element into rearward end position. At least in the case of “true” automatic vehicles, the step-by-step shifting condition can also not be directly selected from the neutral condition.
In the drive condition, the neutral condition can be selected by deflecting the shifting element from the stable position into the forward neutral position, and the reversing condition can be selected by deflecting the shifting element into the forward end position. In addition, the step-by-step condition can be selected by deflecting the shifting element from the stable position in the longitudinal direction of the first shifting channel. In other words, by another deflection or touching of the shifting element in the first shifting channel, the individual forward gears can be manually upshifted or downshifted. Furthermore, a shift into the sports program can take place from the drive condition by way of an “operating element,” such as an S/D key. However, it may also be provided that the S Program can be reached from the drive condition by a one-time deflection of the shift lever in the first shifting channel, and a manual upshift or downshift can take place by a repeated deflection.
In the step-by-step shifting condition, the neutral condition can be selected by deflecting the shifting element from the stable position into the forward neutral position of the second shifting channel, and the reversing condition can be selected by deflecting the shifting element into the forward end position. The drive condition can be selected by deflecting the shifting element from the stable position into the rearward end position of the second shifting channel. Furthermore, a shift can take place from the step-by-step shifting condition by way of an “operating element,” such as an S/D key, into the sports program. Furthermore, naturally, by deflecting or touching the shifting element in the first shifting channel, upshifts or downshifts can be made.
As an alternative or in addition, it can also be provided that a change-over shift can be carried out between the step-by-step shifting condition, the drive condition and the sports program by a movement of the shift lever in the transverse direction with respect to the shifting channels.
The shifting element is preferably constructed as a “joystick.” This means that the shift lever is not “mechanically” connected with the transmission but electrically connected with a transmission control unit which controls the shifting operation in the transmission by way of transmission actuators.
The shifting element or the shift lever is preferably assigned a desired shifting force characteristic. It may, for example, be provided that the shifting force for deflecting the shifting element from the stable position of the first shifting channel into the center position of the second shifting channel is essentially dependent in a linear manner on the deflection path of the stable position. The shifting force for this “transverse movement” may, for example, be constant or increasing in a slightly linear manner.
With respect to the movement of the shifting element in the second shifting channel, a shifting force can be provided which has several maximum values. Starting from the center position, the shifting force first increase to a first maximum when the shift lever is moved into the forward or rearward neutral position. Then the shifting force decreases again slightly, whereby the driver is haptically provided with the feeling that the forward or rearward neutral position has been reached.
When the driver moves the shift lever further toward the front or the rear, the shifting force rises to a second shifting force maximum. This second shifting force maximum is greater than the first shifting force maximum. For selecting the reversing condition or the drive condition by way of the second shifting channel, the driver therefore has to apply a higher shifting force. When the driver overcomes this second shifting force maximum, he haptically receives a feedback because the shifting force will slightly decrease again. This indicates to the driver that he has reached the position for selecting the reversing condition or the drive condition. If he subsequently releases the shift lever, the shift lever will automatically return to the stable position in the first shifting channel.
According to a further development of the invention, a display unit is provided which has a shifting diagram displaying the possible deflecting positions of the shifting element from the stable position. The deflecting positions for selecting the individual actually selectable operating conditions are indicated in the shifting diagram by assigned symbols. In addition to the actual operating condition, preferably only those operating conditions are schematically indicated which can be selected as a function of the actual operating condition.
Preferably, the actual operating condition is visually highlighted in the shifting diagram with respect to the actually selectable operating conditions, for example, by a different color or brightness.
Preferably at least one display element of the display device is visible in the drive condition and in the step-by-step shifting condition, which display element displays the selection option “step-by-step shifting condition” in the drive condition and displays the “manual shifting option” in the step-by-step shifting condition.
According to a further development of the invention, the display device has a luminous marking which indicates the stable position of the shifting element. When the shifting element or the shift lever are deflected, this marking will be extinguished. However, according to a further development of the invention, it may be provided that the luminous marking, which shows the position of the shift lever, will “move along” during a movement of the shift lever in the shifting diagram of the display device.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.